A Novel Illusion of Bars Made from Triangles

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Science  05 Jun 1981:
Vol. 212, Issue 4499, pp. 1172-1175
DOI: 10.1126/science.212.4499.1172


A repetitive pattern of a triangular luminance profile may be perceived as a triangular-wave grating or as a square-wave grating. This illusion may reflect the operation of cortical phase-selective mechanisms that are biased toward particular phase relations and favor abrupt luminance gradients.